I am posting this for a buddy. He has a 24 volt military that he would like to convert to 12 volt what would be required to do this? Any help would be helpful. Thanks in advance.....

alternator, regulator (if he's got an external), fuses, starter....

For the most part all the electrical stuff in the vehicle will work on 12v power just not at full capacity...like the heater blower, wipers, lights. Some of the wiring will have to be replaced as 12V systems draw more amps.